1. Field of the Invention
The present invention relates generally to substrate coaters and, more particularly, to a system and method that allows for the continuous pulling of substrates through a coater, even while a coated portion of the substrate is held stationery for cutting.
2. Background of the Related Art
Coating of substrates in an industrial setting is typically accomplished via the use of coaters, such as drawdown coaters. Such devices allow for the application of coating materials, such as emulsions and solvents, to a sheet of substrate, such as film and paper substrates. Examples of coatings that can be applied to a substrate with a drawdown coater include, but are not limited to any viscous or semi viscous liquid that can be formed into a sheet substrate for medical, industrial, scientific, photographic, artistic, or nutritional purposes.
One common type of coating technique employed is referred to as the “knife-over-roll” coating method. This method relies on a wet coating being applied to a substrate, which then passes through a “gap” between a “knife” and a support roller. As the coating and substrate pass through, the excess is scraped off.
In a production environment, pulling tens or hundreds of feet of substrate at a time from a roll stock requires periodic cutting of the material. During the pause to cut the substrate, an interruption of the coating occurs that results in a line across the casting or coated substrate. Because the coating is thinner at this line and because it is also visually inconsistent with the rest of the coating, the section of substrate having the line is considered unusable for sale, or at least cannot be marketed at the same value.
In addition to the cosmetic anomaly, any coated product of a medicinal nature would exhibit an inconsistent dose. Trimming by hand, which is currently done, results in further loss due to lack of necessary precision, requiring re-cutting of the same ends to square off.